The present invention relates to analysis of digital data, and more particularly to a method of qualified anomaly detection in order to detect and trigger on specific analog anomalies and/or digital data within a qualified area of a serial data stream.
Oscilloscope trigger circuits have become exceedingly complex, enabling a user to trigger on almost any type of analog anomaly within an input electrical signal in order to acquire data for the analysis of the particular anomaly. Some trigger circuits also allow the user to trigger on a particular data word or event within a serial digital data stream. However serial data streams encompass many levels of hierarchy, as exemplified by the OSI (Open System Interconnection) model that defines a networking framework for implementing protocols in seven layers. These serial data streams have framed data accompanied by several higher layer protocols that are used to route/identify the data. This makes debugging of a physical event or anomaly within a specific portion of the serial data stream difficult. Since these serial data streams tend to be quite noisy, analog anomalies may be particularly problematic when the serial data streams are decoded for information content. Such anomalies may result in misinterpretation of the bits within the serial data stream.
Logic analyzers have the capability to trigger on anomalies if they have digital characteristics and thresholds only, but do not have the ability to trigger on analog anomalies representative of signal fidelity.
What is desired is a method of detecting and triggering on specific analog anomalies and/or digital data within a qualified area of the serial data stream.